Method, apparatus, and network device for power control

ABSTRACT

In a method for power control, a user equipment (UE) receives a path loss measurement indicator and at least one parameter sent by a base station and measures a path loss between the UE and at least one uplink serving access point of the UE according to the path loss measurement indicator. An uplink transmitting power adjustment value is calculated according to the measured path loss and the at least one parameter received from the base station. The UE adjusts uplink transmitting power according to the uplink transmitting power adjustment value.

This application is a continuation of U.S. patent application Ser. No.13/235,117, filed on Sep. 16, 2011, which is a continuation ofInternational Application No. PCT/CN2009/070803, filed on Mar. 16, 2009.Each of the above-mentioned patent applications is hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of communicationstechnologies, and in particular, to a method, an apparatus, and anetwork device for power control.

BACKGROUND

In an existing Long Time Evolution (LTE) system, generally a UserEquipment (UE) communicates with only one Access Point (AP) in an uplinkdirection (that is, the UE sends a signal to the AP) and in a downlinkdirection (that is, the AP sends signals to the UE), where the AP iscalled a serving AP, and an uplink serving AP and a downlink serving APis the same AP. The AP is a node including at least a radio frequencytransceiver and may be equipped with one or multiple antenna elements;multiple APs may be distributed or centralized geographically andconnected to an eNodeB over a wired or wireless connection; or the APand eNodeB may be the same physical entity. The relationship between anAP and a cell may be as follows. A cell includes one AP, or a cellincludes multiple APs. For ease of description, the following assumesthat a cell includes one AP.

In such a system, the uplink transmitting power of the UE may be basedon downlink signaling of the base station eNodeB and/or the measurementresult of a radio channel measured by the UE. For example, thetransmitting power of a Physical Uplink Share Channel (PUSCH) of the UEis decided by multiple factors, which include downlink Path Loss(abbreviated to PL) measured by the UE, cell-specific power adjustmentP_(O) _(—) _(NORMINAL) _(—) _(PUSCH)(j) sent by the AP to the UE, andUE-specific power adjustment P_(O) _(—) _(UE) _(—) _(PUSCH)(j) sent bythe AP to the UE. Therefore, the UE receives the downlink signaling sentby the serving AP to obtain P_(O) _(—) _(NORMINAL) _(—) _(PUSCH)(j) andP_(O) _(—) _(UE) _(—) _(PUSCH)(j), measures the downlink signal sent bythe serving AP to obtain the PL, and calculate the uplink transmittingpower value considering other parameters.

In the process of implementing the present invention, the inventor findsthat in the communication system, the introduction of multipletechnologies, such as Coordinated Multi-Point transmission (CoMP),different uplink and downlink serving cells, and relay transmission,brings forth a new scenario. For example, the CoMP technology is animportant way to improve the overall performance of a cell and theperformance of the cell serving a UE at the cell edge, and multiple APsmay coordinate in transmitting and receiving data from the UE (the APsmay be connected to the same eNodeB or to different base stations) andtherefore a new scenario may be introduced, that is, the uplink anddownlink serving APs may be the same or different. If the existinguplink power control algorithm is applied directly, a certain problemmay occur during uplink power control. Specifically, among parameters ofthe uplink power control formula, the cell-specific parameters (such asthe P_(O) _(—) _(NORMINAL) _(—) _(PUSCH)(j) value) and UE-specificparameters (such as the P_(O) _(—) _(UE) _(—) _(PUSCH)(j) value) areobtained by the UE from an AP that sends downlink signaling; if the APis different from the uplink serving AP of the UE, the uplink signalpower obtained according to the parameters does not match the powerexpected by the uplink serving AP. In addition, among the parameters ofthe uplink power control formula, the PL is obtained by the UE bymeasuring downlink signals of an AP. If the AP is different from theuplink serving AP of the UE, the uplink signal power obtained accordingto the PL parameter does not match the power expected by the uplinkserving AP.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method, an apparatus, anda network device for power control to ensure normal uplink transmissionthrough corresponding processing when an AP that sends downlinksignaling to a UE is different from an uplink serving AP of the UE.

Embodiments of the present invention provide the following technicalsolutions.

An embodiment of the present invention provides a method for powercontrol, including if a downlink serving AP of a UE is different from anuplink serving AP of the UE, sending, by a base station, downlinksignaling to the UE so that the UE adjusts uplink transmitting poweraccording to the downlink signaling.

An embodiment of the present invention further provides an apparatus forpower control, including a judging unit, configured to judge whether adownlink serving AP of a UE and an uplink serving AP of the UE is thesame AP, and a sending unit, configured to send downlink signaling tothe UE when the judging unit determines that the downlink serving AP ofthe UE is different from the uplink serving AP of the UE, so that the UEadjusts uplink transmitting power according to the downlink signaling.

An embodiment of the present invention further provides a UE, includinga first receiving unit, configured to receive a PL measurement indicatorand a parameter sent by a base station, a measuring unit, configured tomeasure a PL between the UE and at least one uplink serving AP of the UEaccording to the PL measurement indicator received by the firstreceiving unit, a second calculating unit, configured to calculate anuplink transmitting power adjustment value according to the measured PLand the parameters obtained from the base station, and a first adjustingunit, configured to adjust uplink transmitting power according to theuplink transmitting power adjustment value calculated by the secondcalculating unit.

An embodiment of the present invention further provides a UE, includinga presetting unit, configured to bind change information of a serving APof the UE to a range of an uplink power control parameters of the UEbeforehand, a second receiving unit, configured to receive the changeinformation of the serving AP of the UE and downlink signaling carryinginformation that indicates an uplink transmitting power adjustment sentby a base station, a modifying unit, configured to modify the range ofthe uplink power control parameter according to the change information,and a second adjusting unit, configured to adjust uplink transmittingpower according to the uplink transmitting power adjustment value andthe current range of the uplink power control parameter.

By using the method, apparatus, and network device for power controlprovided by embodiments of the present invention, when the AP that sendsdownlink signaling to the UE is different from the uplink serving AP ofthe UE, corresponding processing is performed to ensure that thecalculated uplink transmitting power matches the expected uplinktransmitting power for uplink transmission, therefore normal uplinktransmission is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of situation 1 of scenario 1 according toa first embodiment of the present invention;

FIG. 2 is a schematic diagram of situation 2 of scenario 1 according tothe first embodiment of the present invention;

FIG. 3 is a schematic diagram of situation 1 of scenario 2 according tothe first embodiment of the present invention;

FIG. 4 is a schematic diagram of situation 2 of scenario 2 according tothe first embodiment of the present invention;

FIG. 5 is a schematic diagram of situation 3 of scenario 2 according tothe first embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an apparatus for powercontrol according to a fifth embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a UE according to a sixthembodiment of the present invention; and

FIG. 8 is a schematic structural diagram of a UE according to a seventhembodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the present invention provide a method, an apparatus, anda network device for power control to ensure normal uplink transmissionthrough corresponding processing when an AP that sends downlinksignaling to a UE is different from an uplink serving AP of the UE. Tobetter explain the purpose, technical solutions, and advantages of thepresent invention, the following describes embodiments of the presentinvention in detail with reference to the accompanying drawings. Itshould be noted that an LTE system is taken as an example and is notconstrued as a limitation on the present invention. Those skilled in theart may understand that the present invention may also be applied inother systems or networks. The serving AP in embodiments of the presentinvention includes an uplink serving AP and a downlink serving AP.

Embodiment 1

When an AP that sends downlink signaling to a UE is different from anuplink serving AP of the UE, an eNodeB obtains parameter of one or someor all uplink serving APs, where the parameter include at least one ofthe following parameters:

1. PL between the uplink serving AP and the UE measured by the uplinkserving AP, where the PL may be obtained by the uplink serving APdetecting an uplink signal sent by the UE and perform calculating;

2. a cell-specific parameter of the uplink serving AP, for example,P_(O) _(—) _(NORMINAL) _(—) _(PUSCH(j)) indicating an expected receivedpower value, parameter α(j) indicating control of interference to othercells, and parameter Ks indicating whether to adjust power according toa MCS in an LTE system; and

3. a UE-specific parameter determined by the uplink serving AP. Itshould be noted that the uplink serving AP determines the parametersaccording to its own scheduling and resources; the UE-specific meansthat parameters may be different for different UEs, because theparameters are determined by the eNodeB or AP according to thescheduling and resources of the eNodeB or AP. An example of suchparameters is P_(O) _(—) _(UE) _(—) _(PUSCH(j)) indicating that the UEis expected to control interference to other cells in the LTE system.

Then the eNodeB calculates an uplink transmitting power adjustment valueof the UE according to the obtained parameters, and transfers the uplinktransmitting power adjustment value to the UE through downlinksignaling; after receiving the downlink signaling, the UE performsmapping according to a corresponding way, and adjusts the uplink powerafter obtaining the uplink transmitting power adjustment value.

The eNodeB calculates the uplink transmitting power adjustment valueaccording to the obtained parameters, which may be one of thecorresponding parameters obtained from all uplink serving APs, or be themaximum value, or minimum value, or average value of the correspondingparameters obtained from all uplink serving APs.

The above process may be performed when the uplink and/or downlinkserving AP of the UE changes. The eNodeB may obtain the parameters ofthe uplink serving AP through various connections between the eNodeB andthe AP such as a fiber connection; when the uplink serving AP of the UEis connected to different eNodeBs, the parameters may also betransferred through connections between eNodeBs, for example,transferred through an X2 interface.

In addition, the relationship between the uplink transmitting poweradjustment value and the downlink signaling may be as follows: Thedownlink signaling may directly include the power adjustment valueinformation, or the power adjustment value information is includedimplicitly in other downlink signaling and transferred to the UE, thatis, higher layer signaling (for example, the higher layer signaling inthe LTE system) or power control signaling in the prior art may be used.The signaling may be transferred to the UE through a broadcast channelor a downlink control channel.

In addition, the eNodeB may transfer the downlink signaling to the UEdirectly, or the eNodeB first transfers the signaling to the AP and thenthe signaling is transferred to the UE through the AP.

For ease of description, the following describes a situation where aneNodeB is connected to two APs and a UE is served by at most two APs asan example.

Scenario 1: The uplink serving AP and the downlink serving AP is thesame AP.

The eNodeB is connected to AP 1 and AP 2, and the uplink and downlinkserving APs of the UE are the same AP. FIG. 1 shows a situation whereonly AP 1 serves the UE, and in this case, good performance can beachieved by the prior art. FIG. 2 shows a situation where both AP 1 andAP 2 serve the UE, and in this case, if the prior art is used, that is,the UE receives downlink signaling from only AP 1, marked as “downlinksignaling” (including power control information P_(O) _(—) _(NORMINAL)_(—) _(PUSCH)(j) and P_(O) _(—) _(UE) _(—) _(PUSCH)(j) information of AP1) in FIG. 1B, and detects only the PL from AP 1 to the UE to calculatethe uplink transmitting power of the UE, the uplink signal sent by theUE arrives at AP 1 at the power expected by AP 1; however, because thepower control information of AP 1 differs from the power controlinformation of AP 2 and the PL from the UE to AP 1 also differs from thePL from the UE to AP 2, the uplink transmitting power of the UE sendingthe uplink signal to AP 2 is too high or too low. Therefore, the priorart cannot work normally in this scenario. The technical solutions ofthe present invention may be implemented well, and specifically, thefollowing steps may be performed:

1. AP 1 detects uplink PL between AP 1 and the UE, and AP 2 detectsuplink PL between AP 2 and the UE, respectively.

2. AP 1 transfers the uplink PL between AP 1 and the UE and parametersrelated to uplink power control to the eNodeB, and AP 2 transfers theuplink PL between AP 2 and the UE and parameters related to uplink powercontrol to the eNodeB, where the parameters related to the power controlmay include at least one of the following content:

(1) expected received power value of the signal of the UE that AP 1 andAP 2 receive, where the value includes at least one of a cell-specificparameter and a UE-specific parameter but is not limited to the aboveparameter, or is the value obtained by calculating through using thecell-specific parameter and the UE-specific parameter, namely, functionsof these parameters, and the present invention does not limit thecalculation method;

(2) compensation coefficient for compensating for the PLs when AP 1 andAP 2 expect the UE to perform power control, where the value may be areal number in the range of 0-1, and the value 1 indicates completecompensation for the PLs; and

(3) whether to consider an MCS to adjust uplink transmitting power whenAP 1 and AP 2 expect the UE to perform power control. For differentcells, when Ks is set to different values, adjustments of uplinktransmitting power are different. For example, for cell 1, if K_(S)=0,it indicates that uplink transmitting power is not adjusted; for cell 2,if K_(S)=1.25, it indicates that the adjustment of uplink transmittingpower is 10 log₁₀(2^(MPR(i)·KS)−1), where MPR indicates the number ofbits transmitted per symbol when an MCS is used. Therefore, when AP 1and AP 2 expect the UE to perform power control, uplink transmittingpower may be adjusted according to different Ks values (for example, thefunction of different Ks values) of cell 1 and cell 2.

3. After receiving the parameter information, the eNodeB may determinepower control parameter of the UE according to the parameters of AP 1and AP 2, for example:

(1) obtain the average value of the expected received power values ofthe uplink signal that AP 1 and AP 2 receive, and use the obtainedaverage value as the power control parameter;

(2) obtain the average value of compensations for the PLs when AP 1 andAP 2 expect the UE to perform power control, and use the obtainedaverage value as the power control parameter; and

(3) if either AP 1 or AP 2 expects the UE to adjust transmitting powerby considering the MCS, determine that the UE adjusts transmitting powerby considering the MCS, and generate corresponding parameterinformation, where the method of adjusting transmitting power byconsidering the MCS is already described above and not further describedhere.

4. The eNodeB sends the above parameters to the UE through downlinksignaling.

5. After receiving the downlink signaling, the UE parses the signalingand adjusts the uplink transmitting power according to the parsingresult.

Scenario 2: The uplink serving AP is different from the downlink servingAP.

The eNodeB is connected to AP 1 and AP 2; because the transmitting powerand antenna configuration of the APs are different, and uplink/downlinkchannel fading between the UE and the APs is varied, the uplink servingAP may be different from the downlink serving AP. For example, thetransmitting power of an AP is higher than that of the UE, andtherefore, the signal sent by the AP can be recovered normally by the UEbut the signal sent by the UE cannot be recovered normally by the AP; inthis case, the downlink serving AP of the UE may be more than the uplinkserving AP of the UE. Further, the situation may cause the AP that sendsdownlink signaling to the UE to be different from the uplink serving APof the UE.

Scenario 2 shows three of the situations. In FIG. 3, the downlinkserving AP of the UE is AP 1; in this case, if the prior art is used,and the UE receives downlink signaling (including power controlinformation P_(O) _(—) _(NORMINAL) _(—) _(PUSCH)(j) and P_(O) _(—) _(UE)_(—) _(PUSCH)(j) information of AP 1) from AP 1, and detects only the PLfrom AP 1 to the UE, however, the uplink serving AP is AP 2, because thepower control information of AP 1 differs from the power controlinformation of AP 2 and the PL of AP 1 also differs from the PL of AP 2,the uplink transmitting power of the UE sending the uplink signal to AP2 is too high or too low. The technical solutions of the presentinvention may be implemented well, and specifically, the following stepsmay be performed:

1. AP 2 detects the uplink PL to the UE.

2. AP 2 transfers the PL and parameters related to uplink power controlto the eNodeB, where the parameters related to the power control mayinclude at least one of the following content:

(1) expected received power value of the signal of the UE that AP 2receive, where the value includes at least one of a cell-specificparameter and a UE-specific parameter but is not limited to theparameters, or is the value obtained by calculating through using thecell-specific parameters and the UE-specific parameters, namely,functions of these parameters, and the present invention does not limitthe calculation method;

(2) compensation coefficient for compensating for the PL when AP 2expects the UE to perform power control, where the value may be a realnumber in the range of 0-1, and the value 1 indicates completecompensation for the PL; and

(3) whether to consider an MCS to adjust uplink transmitting power whenAP 2 expects the UE to perform power control. For different cells, whenKs is set to different values, adjustments of uplink transmitting powerare different. For example, for cell 1, if K_(S)=0, it indicates thatuplink transmitting power is not adjusted; for cell 2, if K_(S)=1.25, itindicates that the adjustment of uplink transmitting power is 10log₁₀(2^(MPR(i)·KS)−1), where MPR indicates the number of bitstransmitted per symbol when an MCS is used. Therefore, when AP 1 and AP2 expect the UE to perform power control, uplink transmitting power maybe adjusted according to different Ks values (for example, the functionof different Ks values) of cell 1 and cell 2.

3. After receiving the information, the eNodeB may determine uplinkpower control parameter of the UE according to the parameters includedin the information.

4. The eNodeB sends the above parameters to the UE through downlinksignaling.

5. After receiving the downlink signaling, the UE parses the signalingand adjusts the uplink transmitting power according to the parsingresult.

In FIG. 4, the downlink serving APs of the UE are AP 1 and AP 2, and theuplink serving AP is AP 2; in this case, if the prior art is used, thatis, the UE receives downlink signaling from AP 1, and detects only thePL from AP 1 to the UE, due to the same cause, the uplink transmittingpower of the UE sending the uplink signal to AP 2 is too high or toolow. The technical solutions of the present invention may be implementedwell, and specifically, the following steps may be performed:

1. AP 2 detects the uplink PL to the UE.

2. AP 2 transfers the PL and parameters related to uplink power controlto the eNodeB, where the parameters related to the power control mayinclude at least one of the following contents:

(1) expected received power value of the signal of the UE that AP 2receive, where the value includes at least one of a cell-specificparameters and a UE-specific parameters but is not limited to theparameters, or is the value obtained by calculating through using thecell-specific parameters and the UE-specific parameters, namely,functions of these parameters, and the present invention does not limitthe calculation method;

(2) compensation coefficient for compensating for the PL when AP 2expects the UE to perform power control, where the value may be a realnumber in the range of 0-1, and the value 1 indicates completecompensation for the PL; and

(3) whether to consider an MCS to adjust uplink transmitting power whenAP 2 expects the UE to perform power control. For different cells, whenKs is set to different values, adjustments of uplink transmitting powerare different. For example, for cell 1, if K_(S)=0, it indicates thatuplink transmitting power is not adjusted; for cell 2, if K_(S)=1.25, itindicates that the adjustment of uplink transmitting power is 10log₁₀(2^(MPR(i)·KS)−1), where MPR indicates the number of bitstransmitted per symbol when an MCS is used. Therefore, when AP 1 and AP2 expect the UE to perform power control, uplink transmitting power maybe adjusted according to different Ks values (for example, the functionof different Ks values) of cell 1 and cell 2.

3. After receiving the information, the eNodeB may determine uplinkpower control parameters of the UE according to the parameters of AP 2.

4. The eNodeB sends the parameters to the UE through downlink signaling.

5. After receiving the downlink signaling, the UE parses the signalingand adjusts the uplink transmitting power according to the parsingresult.

In FIG. 5, the downlink serving AP of the UE is only AP 1, and downlinksignaling is sent to the UE through AP 1, but the uplink serving APs areAP 1 and AP 2; in this case, uplink power control may be performedaccording to the following steps:

1. AP 1 and AP 2 detect uplink PLs to the UE.

2. AP 1 and AP 2 transfer the PLs and parameters related to uplink powercontrol to the eNodeB, where the parameters related to the power controlmay include at least one of the following contents:

(1) expected received power value of the signal of the UE that AP 1 andAP 2 receive, where the value includes at least one of a cell-specificparameters and a UE-specific parameters but is not limited to theparameters, or is the value obtained by calculating through using thecell-specific parameters and the UE-specific parameters, namely,functions of these parameters, and the present invention does not limitthe calculation method;

(2) compensation coefficient for compensating for the PLs when AP 1 andAP 2 expect the UE to perform power control, where the value may be areal number in the range of 0-1, and the value 1 indicates completecompensation for the PLs; and

(3) whether to consider an MCS to adjust uplink transmitting power whenAP 1 and AP 2 expect the UE to perform power control. For differentcells, when Ks is set to different values, adjustments of uplinktransmitting power are different. For example, for cell 1, if K_(S)=0,it indicates that uplink transmitting power is not adjusted; for cell 2,if K_(S)=1.25, it indicates that the adjustment of uplink transmittingpower is 10 log₁₀(2^(MPR(i)·KS)−1), where MPR indicates the number ofbits transmitted per symbol when an MCS is used. Therefore, when AP 1and AP 2 expect the UE to perform power control, uplink transmittingpower may be adjusted according to different Ks values (for example, thefunction of different Ks values) of cell 1 and cell 2.

3. After receiving the parameter information, the eNodeB may determineuplink power control parameters of the UE according to the parameters ofAP 1 and AP 2, for example:

(1) obtain the average value of the expected received power values ofthe uplink signal that AP 1 and AP 2 receive, and use the obtainedaverage value as the power control parameter;

(2) obtain the average value of compensations for the PLs when AP 1 andAP 2 expect the UE to perform power control, and use the obtainedaverage value as the power control parameter; and

(3) if either AP 1 or AP 2 expects the UE to adjust transmitting powerby considering the MCS, determine that the UE adjusts transmitting powerby considering the MCS, and generate corresponding parameterinformation.

4. The eNodeB sends the parameters to the UE through downlink signaling.

5. After receiving the downlink signaling, the UE maps the signaling andadjusts the uplink transmitting power according to the mapping result.

In the first embodiment of the present invention, when the AP that sendsdownlink signaling to the UE is different from the uplink serving AP ofthe UE, corresponding processing is performed to ensure that thecalculated uplink transmitting power matches the expected uplinktransmitting power for uplink transmission, therefore normal uplinktransmission is ensured.

Embodiment 2

In the second embodiment of the present invention, special processing isperformed on the adjustment of a PL on the basis of the firstembodiment. That is, when an AP that sends downlink signaling to a UE isdifferent from an uplink serving AP of the UE, the eNodeB may alsonotify the UE through downlink signaling (PL measurement indicator) todetect PLs of one or some or all uplink serving APs. After receiving thesignaling, the UE detects the PL of the uplink serving AP and appliesthe PL in uplink power control. For example, if the eNodeB notifies theUE to detect the PL of an AP, the UE detects the PL and then calculatestransmitting power according to the compensation coefficient notified bythe eNodeB; if the eNodeB notifies the UE to detect the PLs of multipleAPs, the UE may detect multiple PLs, and then calculate the transmittingpower according to the compensation coefficient notified by the eNodeB.The present invention does not limit the calculation method. For acell-specific parameter of an uplink serving AP and a UE-specificparameter determined by the uplink serving AP, for example, P_(O) _(—)_(UE) _(—) _(PUSCH)(j) indicating that the UE is expected to controlinterference to other cells in an LTE system, see the process in thefirst embodiment. Details are not described here.

The downlink signaling may include an ID of the uplink serving AP orinformation indicating the ID of the uplink serving AP. According to theID of the uplink serving AP or the information indicating the ID of theuplink serving AP, the UE may know a downlink signal sent by the servingAP so as to parse the downlink signaling; or detect the downlink signalto obtain an uplink PL.

In the second embodiment of the present invention, when the AP thatsends downlink signaling to the UE is different from the uplink servingAP of the UE, corresponding processing is performed to ensure that thecalculated uplink transmitting power matches the expected uplinktransmitting power for uplink transmission, therefore normal uplinktransmission is ensured.

Embodiment 3

In this embodiment, change information of a serving AP of a UE is boundto a range of value of a uplink power control parameter on the basis ofthe first embodiment. That is, when an uplink and/or downlink serving APof the UE changes, an eNodeB may notify the UE of the change informationof the serving AP through downlink signaling; the eNodeB may also senddownlink power control signaling to the UE. After receiving the changeinformation of the serving AP, the UE maps the change information to amodification of the range of the uplink power control parameter carriedin the downlink signaling; after the UE receives the downlink powercontrol signaling, the UE parses the downlink power control signalingaccording to a new range of value of the power control parameter andtherefore adjusts the uplink power.

For example, when the uplink serving AP does not change, the range ofuplink power control parameter is [−A, B], where −A indicates theminimum value of a power adjustment and B indicates the maximum value ofthe power adjustment and the unit may be dB. The range of the value ofuplink power control parameter may also be actual values. For example,in an LTE system, the range of DCI format 3 is [−1, 0, 1, 3] dB,indicating one of the four power adjustments may be selected. When thenumber of the uplink serving AP increases, the eNodeB notifies the UEthrough the downlink signaling, and after the UE knows that the numberof the uplink serving AP increases, the UE maps the range of value ofuplink power control parameter to [−C, D] according to the increase ofthe uplink serving AP. When the number of the uplink serving APdecreases, the eNodeB notifies the UE through the downlink signaling,and after the UE knows that the number of the uplink serving APdecreases, the UE maps the range of value of uplink power controlparameter to [−E, F] according to the decrease of the uplink serving AP.After receiving the downlink power control signaling, the UE may map thedownlink power control signaling according to a new range of value ofuplink power control parameter to adjust the uplink power.

In the third embodiment of the present invention, when the AP that sendsdownlink signaling to the UE is different from the uplink serving AP ofthe UE, corresponding processing is performed to ensure that thecalculated uplink transmitting power matches the expected uplinktransmitting power for uplink transmission, therefore normal uplinktransmission is ensured.

Embodiment 4

When an uplink and/or downlink serving AP of a UE changes, an eNodeB maynotify the UE with priority that the uplink serving AP changes; afterreceiving the information, the UE may adjust uplink transmitting powerautomatically. For example, when the number of the uplink serving APincreases, the eNodeB notifies the UE through downlink signaling, andafter knowing the increase of the uplink serving AP, the UE decreasesthe uplink transmitting power value automatically; when the number ofthe uplink serving AP decreases, the eNodeB notifies the UE through thedownlink signaling, and after the UE knows the decrease of the uplinkserving AP, the UE increases the uplink transmitting power valueautomatically.

The eNodeB may notify the UE of the change information of the serving APin the following way: The downlink signaling includes the changeinformation directly, or the change information is included implicitlyin other downlink signaling and transferred to the UE. The uplinktransmitting power value adjusted automatically by the UE may benotified to the UE through the downlink signaling beforehand.

The uplink transmitting power adjustment value may be transferred by theeNodeB to the UE through multiple pieces of power control signaling, andafter receiving the multiple pieces of control signaling, the UEexecutes indicators of all the power control signaling. The range of thepower adjustment may be extended by using this method, therefore thepower control method of the prior art can be used to support embodimentsof the present invention.

For example, in an LTE system, uplink power control indicators may betransferred by using DCI (Downlink Control indicator) format 0 (thevalue range is [−4, −1, 1, 4] dB) and DCI format 3 (the value range is[−1, 0, 1, 3] dB); therefore, if the uplink power control adjustmentvalue is 7 dB, an uplink power control indicator that uses DCI format 0indicating the power adjustment is 4 dB and an uplink power controlindicator that uses DCI format 3 indicating the power adjustment is 3 dBmay be transferred simultaneously. After receiving the two indicators,the UE may adjust the uplink transmitting power by 7 dB.

In the fourth embodiment of the present invention, when the AP thatsends downlink signaling to the UE is different from the uplink servingAP of the UE, corresponding processing is performed to ensure that thecalculated uplink transmitting power matches the expected uplinktransmitting power for uplink transmission, therefore normal uplinktransmission is ensured. Further, the fourth embodiment of the presentinvention can extend the range of power control and ensure the uplinktransmission performance when the uplink serving AP changes.

Persons skilled in the art should understand that part of the steps ofthe method in any embodiment of the present invention may be implementedby a program instructing relevant hardware. The program may be stored ina computer readable storage medium such as a Read Only Memory (ROM), aRandom Access Memory (RAM), a magnetic disk, or a Compact Disk-Read OnlyMemory (CD-ROM).

FIG. 6 is a schematic structural diagram of an apparatus for powercontrol according to the fifth embodiment of the present invention; thepower control apparatus includes a judging unit 610 and a sending unit620, where the judging unit 610 is configured to judge whether adownlink serving AP of a UE and an uplink serving AP of the UE is thesame AP, and the sending unit 620 is configured to send downlinksignaling to the UE when the judging unit 610 determines that thedownlink serving AP of the UE is different from the uplink serving AP ofthe UE, so that the UE adjusts uplink transmitting power according tothe downlink signaling.

Preferably, the apparatus may further include an obtaining unit 630,which is configured to obtain a parameter from at least one uplinkserving AP of the UE. The parameter obtained from the uplink serving APincludes at least one of the following parameters. PL measured betweenthe AP and the UE by the uplink serving AP, a cell-specific parameter ofthe uplink serving AP, and a UE-specific parameter determined by theuplink serving AP.

The apparatus may further include a first calculating unit 640, which isconfigured to calculate an uplink transmitting power adjustment valueaccording to the parameter obtained by the obtaining unit 630;accordingly, the sending unit 620 is further configured to sendinformation indicating the uplink transmitting power adjustment value tothe UE by carrying the information in the downlink signaling.

The first calculating unit 640 calculates the uplink transmitting poweradjustment according to the obtained parameters specifically in thefollowing way: obtaining the maximum value of a corresponding parameterobtained from the at least one uplink serving AP, or obtaining theminimum value of the corresponding parameters obtained from the at leastone uplink serving AP, or obtaining the average value of thecorresponding parameters obtained from the at least one uplink servingAP, or obtaining one of the corresponding parameters obtained from theat least one uplink serving AP.

It should be noted that the sending unit 620 is further configured tosend at least one of the parameters obtained from the obtaining unit andthe UE-specific parameter determined by the uplink serving AP, and a PLmeasurement indicator to the UE by carrying the parameter and theindicator in the downlink signaling. The downlink signaling furtherincludes an ID of the uplink serving AP or information indicating the IDof the uplink serving AP.

In addition, the sending unit 620 is further configured to send thechange information of the serving AP of the UE to the UE so that the UEmodifies the range of uplink power control parameters according to thechange information of the serving AP.

In addition, the obtaining unit 630 is further configured to obtain thechange information of the serving AP of the UE and send the informationto the sending unit 620.

The sending unit 620 is further configured to: send informationincluding the mapping relationship between the change information of theserving AP of the UE and the uplink transmitting power of the UEbeforehand; and when the serving AP of the UE changes, send the downlinksignaling carrying the change information of the serving AP to the UE sothat the UE adjusts the uplink transmitting power automaticallyaccording to the change information.

The sending unit 620 may send the downlink signaling to the UE through abroadcast channel or a downlink control channel. The sending unit 620may also send the downlink signaling to the UE through the downlinkserving AP of the UE.

Embodiments of the apparatus for power detection may be applied inrelated network devices, and the structure of the apparatus is describedabove and not further described here.

FIG. 7 is a schematic structural diagram of a UE according to the sixthembodiment of the present invention. The UE includes a first receivingunit 710, a measuring unit 720, a second calculating unit 730, and afirst adjusting unit 740; where the first receiving unit 710 isconfigured to receive a PL measurement indicator and a parameter sent bya base station, the measuring unit 720 is configured to measure a PLbetween the UE and at least one uplink serving AP of the UE according tothe PL measurement indicator received by the first receiving unit 710,the second calculating unit 730 is configured to calculate an uplinktransmitting power adjustment value according to the measured PL and theparameters obtained from the base station, and the first adjusting unit740 is configured to adjust uplink transmitting power according to theuplink transmitting power adjustment value calculated by the secondcalculating unit 730.

FIG. 8 is a schematic structural diagram of a UE according to theseventh embodiment of the present invention. The UE includes apresetting unit 810, a second receiving unit 820, a modifying unit 830,and a second adjusting unit 840; where the presetting unit 810 isconfigured to bind change information of a serving AP of the UE to arange of an uplink power control parameters of the UE beforehand, thesecond receiving unit 820 is configured to receive the changeinformation of the serving AP of the UE and downlink signaling carryinginformation that indicates an uplink transmitting power adjustment valuesent by a base station, the modifying unit 830 is configured to modifythe range of the uplink power control parameters according to the changeinformation, and the second adjusting unit 840 is configured to adjustuplink transmitting power according to the uplink transmitting poweradjustment value and the current range of the uplink power controlparameters.

By using the method, apparatus, and network device for power controlprovided by the present invention, when the AP that sends downlinksignaling to the UE is different from the uplink serving AP of the UE,corresponding processing is performed to ensure that the relatedparameters for calculating uplink transmitting power match uplinktransmission, therefore normal uplink transmission is ensured.

It should be noted that the present invention is also applicable to arelay transmission system (that is, the AP herein may be replaced by arelay node) or other systems in which an uplink power control parameterdo not match uplink transmission.

Detailed above are a method, an apparatus, and a network device forpower control provided by the present invention. Although the principleand implementation of the present invention are described with referenceto exemplary embodiments, the embodiments are only intended to helpunderstand the solutions of the present invention. In addition,modification or variations may be made to the implementation andapplicability of the present invention by persons skilled in the art.Therefore, the specification shall not be construed as a limitation onthe present invention.

What is claimed is:
 1. A User Equipment (UE), wherein the UE is servedby two uplink serving access points, the UE comprising: a receiver,configured to receive a path loss measurement indicator and at least oneparameter sent by a base station, wherein the path loss measurementindicator is used to initiate measurement of two respective path lossesbetween the UE and the two uplink serving access points; a processorcoupled to the receiver and configured to: measure the two respectivepath losses between the UE and the two uplink serving access pointsaccording to the path loss measurement indicator; calculate an uplinktransmitting power adjustment value according to the measured tworespective path losses and the at least one parameter received from thebase station; and adjust uplink transmitting power according to theuplink transmitting power adjustment value.
 2. A method for powercontrol, the method comprising: receiving, by a user equipment (UE) thatis served by two uplink serving access points, a path loss measurementindicator and at least one parameter sent by a base station, wherein thepath loss measurement indicator is used to initiate measurement of tworespective path losses between the UE and the two uplink serving accesspoints; measuring, by the UE, the two respective path losses between theUE and the two uplink serving access points according to the path lossmeasurement indicator; calculating an uplink transmitting poweradjustment value according to the measured two respective path lossesand the at least one parameter received from the base station; andadjusting, by the UE, uplink transmitting power according to the uplinktransmitting power adjustment value.
 3. The method of claim 2, whereinthe uplink transmitting power adjustment value is calculated by the UE.